The study ‘Dugong distribution, habitat and risks due to fisheries and other anthropogenic activities in India’, by the Wildlife Institute of India, pointed out that in the Gulf of Kutch, more than 50% of boats used were in heavy fishing boat category. This was a major threat as heavy boats cause excessive damage to seagrass beds. Also, some fishermen said excessive hunting in the past was responsible for the decline of the dugong in the Gulf of Kutch.
Gill nets are most dangerous and if a dugongs die when accidentally caught in them. Catches in gill nets are one of the major causes of dugong mortality. Gill nets alone form 63% of the total gear used, followed by purse seines (35%), beach seines (1%) and long lines (1%). Usage of gill nets was highest in Kutch and the Mannar-Palk Bay area. In the Gulf of Kutch over 65% of fishermen use gill nets. According to the study, a high proportion of respondents left gill nets untended for over 2-3 hours, effectively reducing the possibility of an entangled dugong being spotted and released in time.
Although hunting has been totally banned in India, dugong meat is highly prized and considered a delicacy. Its consumption has been reported in the Gulf of Mannar, Palk Bay and Andaman and Nicobar islands. In the Gulf of Mannar and Palk Bay, gill nets, shore seines, trawl nets, drift nets, ray nets and explosives were used to hunt dugongs. Capture numbers were 25 dugongs per year in 1960-1980 and 200 dugongs per year in 1983-1984. This dropped to 9 dugongs per year in 1986-1988. Also, 19% of respondents said that they would eat or sell dugong meat if caught in their net.
Unintentional dugong mortality is caused by boat strikes and propeller injuries when motorized boats traverse shallow feeding grounds. Fast-moving boats give dugongs; less time to evade a collision. With 3.5% of daytime spent resting at the surface of the water, dugongs are vulnerable to boat strikes. Compared to solitary individuals, mother-calf pairs spend more time near the surface, and are hence more prone to accidents. Another threat to dugong habitat is trawl, which degrades seagrass meadows by uprooting rhizomes and removing healthy leaves.
2013 Bennett, Coleman & Co. Ltd.